text stringlengths 1 81 | start float64 0 10.1k | duration float64 0 24.9 |
|---|---|---|
>> -This was the maiden
voyage of the Ariane 5. | 4,798.15 | 2.91 |
And its destruction took
place because of a flaw | 4,801.06 | 2.9 |
embedded in the rocket's software. | 4,803.96 | 1.862 |
-The problem on the Ariane was
that there was a number that | 4,805.822 | 2.458 |
required 64 bits to express. | 4,808.28 | 2.32 |
And they wanted to convert
it to a 16-bit number. | 4,810.6 | 2.99 |
They assumed that the
number was never going | 4,813.59 | 2.02 |
to be very big, that most of those
digits in a 64-bit number were zeroes. | 4,815.61 | 5.37 |
They were wrong. | 4,820.98 | 1.46 |
>> -The inability of one
software program to accept | 4,822.44 | 2.62 |
the kind of number generated by
another was at the root of the failure. | 4,825.06 | 4.45 |
Software development had become a
very costly part of new technology. | 4,829.51 | 4.84 |
The Ariane rocket have been very
successful, so much of the software | 4,834.35 | 3.79 |
created for it was also
used in the Ariane 5. | 4,838.14 | 3.41 |
>> -The basic problem was that the Ariane
5 was faster, accelerated faster. | 4,841.55 | 6.39 |
And the software hadn't
accounted for that. | 4,847.94 | 3.51 |
>> -The destruction of the rocket
was a huge financial disaster, | 4,851.45 | 3.61 |
all due to a minute software error. | 4,855.06 | 3.73 |
But this wasn't the first
time data conversion problems | 4,858.79 | 2.42 |
had plagued modern rocket technology. | 4,861.21 | 3.61 |
>> -In 1991, with the start
of the first Gulf War, | 4,864.82 | 3.23 |
the Patriot Missile
experienced a similar kind | 4,868.05 | 2.52 |
of number conversion problem. | 4,870.57 | 2.23 |
And as a result, 28 people,
28 American soldiers, | 4,872.8 | 3.29 |
were killed, and about
100 others wounded, | 4,876.09 | 2.99 |
when the Patriot, which was supposed
to protect against incoming scuds, | 4,879.08 | 3.7 |
failed to fire a missile. | 4,882.78 | 3.05 |
>> -When Iraq invaded Kuwait, and America
launched Desert Storm in early 1991, | 4,885.83 | 5.84 |
Patriot Missile batteries were deployed
to protect Saudi Arabia and Israel | 4,891.67 | 4.11 |
from Iraqi Scud missile attacks. | 4,895.78 | 3.45 |
The Patriot is a US medium-range
surface to air system, manufactured | 4,899.23 | 4.58 |
by the Raytheon company. | 4,903.81 | 1.96 |
>> -The size of the Patriot interceptor
itself is about roughly 20 feet long. | 4,905.77 | 6.57 |
And it weighs about 2,000 pounds. | 4,912.34 | 2.89 |
And it carries a warhead of about,
I think it's roughly 150 pounds. | 4,915.23 | 4.09 |
And the warhead itself is
a high explosive, which | 4,919.32 | 4.61 |
has fragments around it. | 4,923.93 | 3.4 |
The casing of the warhead is
designed to act like buckshot. | 4,927.33 | 4.35 |
>> -The missiles are carried
four per container, | 4,931.68 | 2.43 |
and are transported by a semi trailer. | 4,934.11 | 3.02 |
>> -The Patriot anti-missile system
goes back at least 20 years now. | 4,937.13 | 7.8 |
It was originally designed
as an air defense missile | 4,944.93 | 3.49 |
to shoot down enemy airplanes. | 4,948.42 | 2.3 |
In the first Gulf War,
when that war came along, | 4,950.72 | 3.78 |
the Army wanted to use it to
shoot down scuds, not airplanes. | 4,954.5 | 5.245 |
>> The Iraqi Air Force was
not so much of a problem. | 4,959.745 | 3.875 |
But the Army was worried about scuds. | 4,963.62 | 3.05 |
And so they tried to
upgrade the Patriot. | 4,966.67 | 3.5 |
>> -Intercepting an enemy
missile traveling at mach 5 | 4,970.17 | 2.63 |
was going to be challenging enough. | 4,972.8 | 3.03 |
But when the Patriot
was rushed into service, | 4,975.83 | 2.66 |
the Army was not aware of an
Iraqi modification that made | 4,978.49 | 4.37 |
their scuds nearly impossible to hit. | 4,982.86 | 3.07 |
>> -What happened is the scuds that
were coming in were unstable. | 4,985.93 | 4.81 |
They were wobbling. | 4,990.74 | 0.952 |
The reason for this was
the Iraqis, in order | 4,991.692 | 3.218 |
to get 600 kilometers
out of a 300 kilometer | 4,994.91 | 3.37 |
range missile, took weight
out of the front warhead. | 4,998.28 | 3.42 |
They made the warhead lighter. | 5,001.7 | 1.69 |
>> So now the Patriot is
trying to come at the Scud. | 5,003.39 | 3.94 |
And most of the time, the
overwhelming majority of the time, | 5,007.33 | 2.9 |
it would just fly by the Scud. | 5,010.23 | 2.71 |
Once the Patriot system operators
realized the Patriot missed its target, | 5,012.94 | 4.32 |
they detonated the Patriot's warhead
to avoid possible casualties if it | 5,017.26 | 4.43 |
was allowed to fall to the ground. | 5,021.69 | 2.88 |
>> -That was what most people saw,
those big fireballs in the sky, | 5,024.57 | 4.22 |
and misunderstood as
intercepts of Scud warheads. | 5,028.79 | 5.76 |
>> -Although in the night
skies, Patriots appeared | 5,034.55 | 2.08 |
to be successfully
destroying Scuds, at Dhahran, | 5,036.63 | 3.74 |
there could be no mistake
about its performance. | 5,040.37 | 2.99 |
There, the Patriot's radar system
lost track of an incoming Scud, | 5,043.36 | 4.61 |
and never launched due
to a software flaw. | 5,047.97 | 2.751 |
It was the Israelis who first discovered
that the longer the system was on, | 5,054.09 | 4.85 |
the greater the time discrepancy
became, due to a clock embedded | 5,058.94 | 3.75 |
in the system's computer. | 5,062.69 | 2.12 |
>> -About two weeks before
the tragedy in Dhahran, | 5,064.81 | 3.4 |
the Israelis reported to
the Defense Department | 5,068.21 | 2.56 |
that the system was losing time. | 5,070.77 | 1.82 |
After about eight hours or running,
they noticed that the system | 5,072.59 | 2.77 |
was becoming noticeably less accurate. | 5,075.36 | 2.36 |
The Defense Department responded by
telling all of the Patriot batteries | 5,077.72 | 4.18 |
to not leave the systems
on for a long time. | 5,081.9 | 3.05 |
They never said what a long time was--
eight hours, 10 hours, 1,000 hours. | 5,084.95 | 4.21 |
Nobody knew. | 5,089.16 | 2.2 |
>> -The Patriot battery
stationed at the barracks | 5,091.36 | 2.02 |
at Dhahran and its flawed internal
clock had been on over 100 hours | 5,093.38 | 4.97 |
on the night of February 25th. | 5,098.35 | 3.32 |
>> -It tracked time to an accuracy
of about a tenth of a second. | 5,101.67 | 4.247 |
Now, a tenth of a second
is an interesting number, | 5,105.917 | 2.083 |
because it can't be expressed
in binary exactly, which | 5,108 | 3.92 |
means it can't be expressed exactly
in any modern digital computer. | 5,111.92 | 4.9 |
It's hard to believe. | 5,116.82 | 1.72 |
>> But use this as an example. | 5,118.54 | 2.67 |
Let's take the number one third. | 5,121.21 | 2.33 |
One third cannot be
expressed in decimal exactly. | 5,123.54 | 3.81 |
One third is 0.333
going on for infinity. | 5,127.35 | 4.73 |
>> There is no way to do that with
absolute accuracy in decimal. | 5,132.08 | 4.4 |
That's exactly the kind of problem
that happened in the Patriot. | 5,136.48 | 3.08 |
The longer the system ran, the
worse the time error became. | 5,139.56 | 4.54 |
>> -After 100 hours of operation, the
error in time was only about one third | 5,144.1 | 4.79 |
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